Cost. Hindu Indian rockets are 15pts and Muslim Indian rockets are 30pts. They appear to be otherwise identical so which one is incorrect?Deployment. Do they deploy first like other artillery, or at the same time as other units?Range. In theory they can fire 72". Can you choose a target out to that range or is this the maximum overshoot range?Movement. Can they move or pivot and are there penalties for doing-so?Firing-arc. To target an enemy, do they fire in a narrow straight line, or a base-width straight-line, or in a normal missile-arc? Presumably they use the normal target-priorities and cannot fire blind.
Do they act as other artillery if shot-at or charged? Can they fight-back?
If a mounted-unit which is overshot by rockets passes its cohesion test, does it become immune to further such tests?
If a rocket-battery with a crew of 5 models scores a hit near an enemy unit, does it affect five 20mm circles or one 100mm circle?

While you're thinking about the answers to the original questions, here's two more.
Rightly or wrongly I envisage rockets being launched up at an angle, therefore do they have a minimum targeting range?
Are they formed troops for the purposes of breakpoint?

A rocket battery with 2 crew costs 30 points.
Rockets deploy at the same time as other artillery. They may fire at any visible target out to their maximum possible range; there is no minimum range. Normal target priorities apply.
They move/pivot as if light artillery and respond to charges as artillery.
A rocket base counts as formed open order, until at least half the crew (round up) are lost (so unformed when 1 of 3 are lost and so on).
When targeting an enemy assume shooting in a narrow line from the centre of the base front. The blast area is a single circle the width of which is determined by the number of crew.
Units forced to take cohesion tests by rockets must do so each time the cause is present.

"No one ever achieved anything without making a few mistakes along the way"

Thanks for the response Martin, all seems clear now.
I have used a pair of rocket batteries in four games now. In the first three games they didn't trouble anyone. In game four they woke-up.
In turn 1 they targeted an enemy archer unit and hit it causing 10 casualties.
In turn 2 they targeted a nafatun unit and caused 2 casualties.
In turn 3 they missed their target and exploded in no-mans land.
In turn 4 they missed their target but flew over the top of one of my elephants, causing it to stampede. Of course it was the elephant with my general on-board.
Will I learn from this lesson? Maybe.